Balancing Resistive Loads in Odd-Column Touch Displays
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Solution Overview
Problem
In touch display devices with TDDI architecture, significant differences in resistive loads between common voltage sources can cause uneven display brightness and split-screen visual effects, particularly when the number of touch electrode columns is odd.
Innovation Solution
The implementation of a drive chip with two common voltage sources and a touch display panel layout where touch electrodes are divided into regions and halves, with specific coupling to each voltage source to balance resistive loads, using a middle column and regions with mirror-symmetric arrangements to ensure equivalent resistive loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all touch electrodes are coupled to a single common voltage source, then the circuit design is simple, but significant resistive load differences cause uneven display brightness and split-screen visual effects
Solution Approach 1:
The patent divides the touch electrode array into multiple groups, each coupled to a separate common voltage source. Specifically, touch electrodes are segmented by rows or columns and assigned to different VCOM sources, balancing the resistive load across each voltage source and eliminating the split-screen effect while maintaining manageable circuit complexity through systematic grouping.
Solution Approach 2:
The patent applies different coupling configurations to different regions of the touch electrode array. By assigning specific rows or columns to specific common voltage sources based on their spatial location, the system achieves local optimization of resistive load distribution, ensuring uniform display brightness across the entire panel while maintaining overall circuit simplicity.
2Illumination intensity
If touch electrodes are divided into multiple regions coupled to different common voltage sources, then display brightness uniformity is improved, but the coupling configuration becomes complex
Solution Approach 1:
The patent employs asymmetric coupling configurations where the division of touch electrodes into regions with different common voltage sources creates an intentional asymmetric pattern. This asymmetric arrangement strategically balances the resistive load across voltage sources while following systematic rules that prevent excessive complexity, achieving brightness uniformity through purposeful asymmetric design rather than symmetric simplicity.
Solution Approach 2:
The patent introduces a new dimension of organization by coupling touch electrodes to common voltage sources based on spatial dimensions (rows or columns) rather than simple sequential numbering. This dimensional approach to grouping allows the system to balance resistive loads across multiple voltage sources while maintaining a regular, predictable coupling pattern that avoids excessive configuration complexity.
Data Source
AI summary
A touch display device including a drive chip and a touch display panel is provided. The drive chip includes a first common voltage source and a second common voltage source. The touch display panel includes a plurality of touch electrode including a plurality of rows and columns, wherein the number of columns is odd-numbered. The touch display panel includes a middle column, a first region and a second region. The middle column is interposed between the first region and the second region having the same number of touch electrodes. The touch electrodes in the first region and that in the second region are coupled to the first common voltage source and the second common voltage source respectively. The middle column is divided into a first half and a second half by a reference line. The first half and the second half have the same number of touch electrodes.